Through-piping arrangement for air conditioning unit



United States Patent Ofitice 3,056,958 Patented Aug. 28, 1962THROUGH-PIPING ARRANGEMENT FOR AIR CONDITIONING UNIT Richard E.Allender, Davenport, Iowa, assignor to American Air Filter Company,1116., Louisville, Ky., a corporation of Delaware Filed Apr. 12, 1961,Ser. No. 102,502 6 Claims. ((31. 62-285) This invention relatesgenerally to air conditioning apparatus and relates particularly to animproved throughpiping arrangement for a remote air conditioning unit.While the invention is suitable for embodiment in various kinds ofremote air conditioning units, it will be primarily described inconnection with an air conditioning unit ventilator.

A through-piping arrangement, as that term is used herein, means thatforced water supply and return piping for a series of remote airconditioning units in one water circuit passes through, rather thanaround, the cabinet of the unit. This arrangement is frequently providedwhen the piping between units in adjacent rooms is mounted on the wallwith pipe covers or other structure hiding the pipes between the units.

One object of the present invention is the provision ofa relativelysimple through-piping arrangement for an air conditioning unitventilator (i.e., one that is adapted to selectively utilize forced hotor chilled water as the tempering medium).

Another object is the provision of a through-piping arrangement whereinit is not necessary to insulate all of the supply and return pipingwithin the unit ventilator; thus providing not only a saving ininsulation but also a saving in space required to accommodate thepiping.

These and other objects of the invention are attained by providing aconstruction wherein the heat exchanger of the unit ventilator is sodisposed as to permit installation of the through supply and returnpiping closely adjacent the heat exchanger and in a position so that thecondensate drip pan for the heat exchangeralso serves to collectcondensate dripping from the supply and return piping.

More specifically, in accordance with the invention, I provide, in anair conditioning unit ventilator of the face and bypass damper type, aheat exchanger or coil having its bottom adjacent the rear wall of thecabinet and being tilted forwardly, a condensate drip pan underlying thebottom edge of the heat exchanger and spaced therebelow, a water supplypipe extending through the space between the drip pan and the bottomedge of the coil, and a water return pipe above the supply pipe andextending through the space between the downstream face of the coil andthe rear wall of the cabinet. With this through-piping arrangement,those lengths of the supply and return pipe overlying the drip pan neednot be insulated, thus saving insulation and requiring less space forthe through piping. Further, a savings is effected of the pipe and pipefittings such as would be required if the piping were to loop around thecentral part of the unit ventilator, and the piping does not contributesignificantly to the space problem frequently encountered in attemptingto get everything needed into a unit ventilator having a limited sizecabinet.

The invention will be further described in connection with theaccompanying drawing illustrating one embodiment incorporating theprinciples of the invention by way of example, and wherein:

FIGURE 1 is a somewhat diagrammatic vertical sectional view of a unitventilator having the through-piping arrangement of the invention;

FIGURE 2 is a fragmentary vertical sectional view showing therelationship, in somewhat more detail than in FIGURE 1, between thecoil, through-piping arrange ment, and the drip pan of the unitventilator;

FIGURE 3 is a broken top View of a unit ventilator incorporating thethrough-piping arrangement, this view showing the piping connectionsmade and the piping extending beyond the ends of the unit ventilatorthrough pipe covers;

FIGURE 4 is an end view of a unit ventilator adapted to incorporate thethrough-piping arrangement, the connections between the through-pipingand the coil not being shown in this view;

FIGURE 5 is a fragmentary front view of the end compartment of the unitventilator of FIGURE 4; and

FIGURE 6 is a fragmentary front view of the left end portion of the unitventilator and the piping and cover extending beyond the unitventilator, this view showing the connections between the piping andcoil.

The unit ventilator illustrated in the drawing is similar, in respect tothe general arrangement of major parts, to the unit ventilator describedand claimed in Baker et al. US. Patent 2,909,043. As is conventional,the interior of the unit ventilator is vertically divided into threeportions (FIGURE 3) including a left-end compartment generallydesignated 2, a right-end compartment generally designated 4, and acentral portion 6; the divisions being made by the left and rightvertical partitions 8 and 10. The interior components illustrated inFIGURES 1 and 2 are within this central portion 6 which serves as acentral passageway for the air between the air inlets and the airoutlets of the unit ventilator.

. The unit is typically mounted with its rear side against an exteriorbuilding wall 12 containing an outdoor air inlet 14 for admitting freshair to the lower part of the central portion. Recirculation air isadmitted through a room air inlet 16, the proportions of fresh andrecirculated air admitted being controlled through operation of theprimary dampers generally designated 18 and operable between alternateextreme positions shown by the solid and dotted line positions. The airdrawn into the unit through the inlets is'drawn upwardly and through thecentral portion of the unit ventilator by a series of fans 20 positionedbelow the top wall 22 which contains air outlet openings 24 throughwhich air is discharged into the room.

In passing upwardly through the central passageway, also designated 6,and which is defined on opposite ends by the opposite verticalpartitions 8 and 10, and at the front and rear by the respective frontand rear walls 26 and 28, the air passes through a filter 30 and is thendirected through or around the heat exchanger or coil 32 in accordancewith the position of the bypass damper 34 operable between the oppositeextreme positions illustrated by the solid and dotted line positions ofthe damper.

The coil 32 is positioned with its bottom edge 36 adjacent the rear Wall28 of the central passageway, and is tilted forwardly so that itsupstream and downstream faces 33 and 40 respectively are inclined withrespect to a vertical plane. The bypass air passageway, through whichair directed around the coil passes, is forwardly of the coil and isdefined along its rear by a baffle 42 depending from the top edge of thecoil and cooperating with frame structure in which the bypass damper 34is supported, a preferred bypass damper and frame structure beingdisclosed in copending Selhost U.S. patent application Serial No.94,744, filed March 10, 1961.

A drip pan 44 substantially underlies the bottom edge of the coil tocatch condensate dripping from the coil when chilled water is beingcirculated. This pan may conveniently be attached along its forward edgeto the rear edge of the auxiliary frame in which the air filter 30 i isplaced. This permits the pan to be Withdrawn forwardly through the sameaccess opening through which the air filter is withdrawn. The pan issupported on an 23 underlying plate 46 extending between the oppositevertical partitions and having a forward edge generally delineating therear edge of the opening above which the filter is situated.

It will be observed in FIGURES l and 2 that the inclination of the coil32 relative to the rear wall 23 results in a generally s -shaped spacebetween the rear wall and the downstream face 4% of the coil, and thespacing of the drip pan 44 below the coil leaves a space therebetween.In accordance with the invention, the V-shaped space accommodates thereturn water pipe 4? of the. through-piping, and the space between thecoil and the drip pan accommodates the supply water pipe Ell of thethrough-piping.

Turning now to FIGURE 3, both the supply and return pipe extend throughthe central air passageway, slightly forward of the rear wall 28, withrespective opposite ends projecting through the vertical partitions 3and it Since the supply and return pipes are vertically aligned, onlythe return pipe 48 is visible in FEGURE 3. Each pipe comprises astraight portion which extends from the one end compartment through thecentral air passageway 6 to the opposite end compartment, and anexpansion-loop portion 52 in the opposite end compartment. The outer endof the expansion-loop extends slightly beyond the opposite endcompartment to permit a connection to be made with the piping whichextends to unit ventilators in adjacent rooms. In the drawing, theexpansion-loop portion is shown in the right-end compartment 4, with theleft-end compartment 2 providing space for making the connectionsbetween the through-piping and the coil $2.

Each vertical partition 8 and ill is made up of a number of separatepanels which in assembled form make up what is herein called thevertical partitions. The parts which comprise the vertical partitionsare generally delineated in FIGURES 4 and 5 and include three mainparts, a lower panel 54- corresponding to the end of the primary damperportion of the central passageway, an upper panel 56 generallycorresponding to the end of the fan section of the central passageway,and an intermediate panel 58 generally corresponding to the end of thecoil and bypass section of the central passageway. Since the provisionof through-piping for any particular arrangement is optional with thecustomer, those parts of the vertical partitions through which thethrough-piping passes and which support the piping when it is to be usedare characterized as adapter pieces. The upper adapters 6t) are flat,plate-like members secured along their upper edges to a depending flangeof ledge 66 formed along the lower edge of the upper panel 56, with thefront and bottom marginal edges of the pieces being lapped by the edgesof the cut-out of the intermediate panel 58. The lower adapters 62 areinwardly open shell-like pieces secured in the illustrated positionadjacent the rear wall 28. Each adapter has a hole in which a grommet 64is mounted and through which the piping passes.

In the factory installation of the through-piping, the through-piping ismounted in place before the coil 32, the bypass damper 3d and theintermediate panels 58 of the vertical partition are installed. Theadapters an and as are first secured in place to the upper and lowerpanels 56 and 54 with the through-piping mounted to extend through thecentral passageway. The coil and intermediate panels are then added andthe bypass damper section may then be installed. It will be observed inFIG- URES 4 and 5 that the supply and return tappings 63 and '70respectively of the coil project through one of the intermediate panels58. The relationship between the through-piping location and the coiltappings in the left end compartment is shown in FIGURES 4 and 5 beforethe connections between through-piping and the coil are made.

The fittings used to connect each through-pipe with its respective coiltapping is shown in FIGURES 3 and 6. The fittings include a T 72, anelbow '74 and a combination balancing and shut-off valve 76. Theshut-ofi d valves may be closed tightly to permit removal of anindividual unit coil without draining the water from the circuit inwhich the individual unit is installed. An air vent 7% is preferablyprovided in the return T 7'2 in accordance with conventional practice.

As will be appreciated, the through-piping arrangement described isintended for a wall mounted piping circuit serving a number ofunitventilators. Thus, the supply and return piping which connects the unitventilators in adjacent rooms is shown in FIGURES 3 and 6 extendingbeyond the ends of the unit ventilator. Both the supply pipe extension86 and the return pipe extension 82 are usually hung from the wall and apipe cover 84 or similar structure is used to cover the pipe. Insulatingthe piping extending through the central passageway 6 is not required.However all piping and fittings in the end compartments and between unitventilators must be insulated.

In the typical operation of a bypass damper type unit ventilator servedby a forced Water system, the water will normally be continuouslycirculated to and through all of the coils. The degree to which the airpassing through the unit ventilator is heated or cooled is dependentupon the position of the bypass damper since so-called valve control ofwater How to each coil is normally not used. if chilled water is beingcirculated, condensate forming on the coil and the through-piping withinthe central passageway falls into the common drip pan. If hot water isbeing circulated, the problem of condensate collection does not exist ofcourse. However, in either case, the through-piping Within the centralpassageway does serve as a miniature heat exchanger in itself when airis passing around it, and does not act as an uncontrolled heat source aswould be the case where only hot water was to be used and uninsulatedthrough-piping looped around the central passageway within the cabinet.

Any given piping circuit containing a number of unit ventilators may bearranged for either direct or reverse return, and the mains for theparticular circuit may be arranged for up-feed or down-feed With dueconsideration being given to the proper air venting and drainingpractices.

It will be appreciated that while the invention has been described inconnection with a unit ventilator, the principles thereof are equallyapplicable to an air conditioning unit which does not have provision forvarying the quantity of outdoor air in the manner of a unit ventilator.Thus, for example, the invention could also be embodied in a remotefan-coil unit adapted to utilize hot and chilled water as the temperingmedium.

The invention claimed is:

1. In a through-piping arrangement for a remote air conditioning unithaving a cabinet enclosing a pair of opposite end compartments and acentral air passageway with a forwardly inclined coil in said centralair passageway of the type adapted to selectively receive hot andchilled water: drip pan means generally underlying the bottom side ofsaid coil and of a sufficiently limited width that it does not extendforwardly to any substantial degree below the front face of said coil; apair of pipes extending from one end compartment through said centralpassageway into the other end compartment for conveying said watertherethrough, said pipes being generally aligned with each other invertically spaced relation and collectively overlying said drip panmeans in aligned relation within said central passageway so thatcondensate forming on and dropping from said pipes during a period ofchilled water circulation will be received by said drip pan means whichalso serves said coil.

2. The through-piping arrangement specified in claim 1 wherein: saidpair of pipes are uninsulated in said central passageway.

3. The through-piping arrangement specified in claim 1 wherein: saiddrip pan means is spaced sufiiciently below the bottom side of said coilto accommodate one of said pair .of pipes in the space between said coiland said drip pan; and the other of said pair of pipes extends throughsaid central passageway adjacent the downstream face of said coil.

4. In a remote air conditioning unit including a cabinet having an airinlet and air outlet and blower means for inducing the flow of airthrough a central air passageway defined by a front wall and a rear walland opposite end walls: a heat exchanger, adapted to selectively receivea tempering medium of one temperature character and another, disposedwithin said passageway between said opposite end walls and extendingforwardly and upwardly with its rear bottom corner adjacent said rearwall; a condensate pan spaced below and underlying the bottom edge ofsaid heat exchanger to define a space therebetween, said pan being of asufliciently limited width that it does not extend forwardly to anysubstantial degree below the 'front face of said heat exchanger; asupply pipe for carrying a supply of said tempering medium through saidpassageway, extending through said space and having opposite endsprojecting through the respective opposite end walls; and a return pipefor returning said tempering medium through said passageway, extendingthrough another space defined by the rear face of said heat exchangerand the rear wall, and having opposite ends projecting through therespectively opposite end walls.

5. In a unit ventilator including a cabinet having an air inlet and airoutlet and blower means for inducing the flow of air into said airinlet, through a central air passageway defined by a front and rear walland opposite end walls, and out of said air outlet: a heat exchanger,adapted to selectively receive a tempering medium of one temperaturecharacter and another, extending forwardly across a portion of saidcentral air passageway in inclined relation to the vertical front andrear walls of said central air passageway; a partition underlying thelower edge of said heat exchanger, said partition being of asufiiciently limited width that it does not extend forwardly to anysubstantial degree below the front face of said heat exchanger; acondensate drip pan of a width generally co-extensive with saidpantition width overlying said partition and spaced below the lower edgeof said heat exchanger to receive condensate therefrom; a pair of pipesfor carrying said tempering medium passing through said opposite endwalls in an aligned disposition above said condensate drip pan so thatcondensate dropping from said pipes will be received by said pan.

6. In air conditioning apparatus of the unit ventilator type having acabinet enclosing opposite end compartments and a central air passagewayseparated from said end compartments by correspondingly oppositevertical partitions: a heat exchanger adapted to selectively receive aheating or a cooling medium disposed to extend across a portion of saidcentral air passageway in inclined relationship to the rear wall of saidcabinet, the rear bottom corner of said heat exchanger being adjacentsaid rear wall so that a lower, downwardly-open V-shaped space is formedbetween the bottom edge of said heat exchanger and said rear wall, andan upper, upwardly-open V-shapedspace is formed between the rear face ofsaid heat ex changer and said rear wall; a condensate drip pan spacedbelow the bottom edge of said heat exchanger in a position to receivecondensate dripping from said heat exchanger, said pan being of asufliciently limited width that it does not extend forwardly to anysubstantial degree below the front face of said heat exchanger; a returnwater pipe extending from one end compartment to the other through saidupper space in said central passageway, said return pipe beingvertically aligned with said pan; and a supply water pipe extending fromone end compartment to the other through said lower space in saidcentral passageway, said supply pipe also being vertically aligned withsaid pan.

References Cited in the file of this patent UNITED STATES PATENTS2,363,294 Carrier Nov. 21, 1944 2,818,217 McElgin -Dec. 31, 19572,909,043 Baker Oct. 20, 1959

